On 3/2/23 09:51, Bart Van Assche wrote: > On 3/1/23 16:06, Damien Le Moal wrote: >> On 3/2/23 08:50, Bart Van Assche wrote: >>> On 3/1/23 15:34, Khazhy Kumykov wrote: >>>> - There’s already support in the kernel for marking zones >>>> online/offline and cmr/smr, but this is fixed, not dynamic. Would >>>> there be hiccups with allowing zones to come online/offline while >>>> running? >>> >>> It may be easier to convince HDD vendors to modify their firmware such >>> that the conventional and SMR zones are reported to the Linux kernel as >>> different logical units rather than adding domains & realms support in >>> the Linux kernel. If anyone else has another opinion, feel free to share >>> that opinion. >> >> That would not resolve the fact that each unit would still potentially have a >> mix of active and inactive areas. Total nightmare to deal with unless a zone API >> is also exposed for any user to figure out which zone is active. >> That means that we would need to always expose these drives as zoned, using a >> very weird zone model as zone domains/zone realms do not fit at all with the >> current host-managed model. Lots of places need changes to handle these drives. >> This will make things very messy all over. > > Do users need all the features that are supported by the domains & > realms model? If not: what I had in mind is to let the HDD expose two > logical units to the operating system that each have a contiguous range > of active zones and hence not to support inactive zones. But that is the issue: zones in the middle of each domain can be activated/deactivated dynamically using zone activate command. So there is always the possibility of ending up with a swiss cheese lun, full of hole of unusable LBAs because the other domains (other LUN) activated some zones which deactivate the equivalent zone(s) in the other domain. With your idea, the 2 luns would not be independent as they both would be using LBAs are mapped against a single set of physical blocks. Zone activate command allows controlling which domains has the mapping active. So activating a zone in one domains results in the zone[s] using the same mapping in the other domain to be deactivated. > > Thanks, > > Bart. > -- Damien Le Moal Western Digital Research
